Implementation: BlinnPhongLighted Cube

Overview 

In previous examples, we saw that Position, Color, Texture data were sent to draw cubes. In this post we  will discuss how to implement  Blinn Phong lighting model. For this surface normals needs to be sent as VBO data. They look as shown at the bottom. They look elongated because aspect ratio is not applied.

Details

System  class diagram

BlinnPhongLightedTexCube derives from TexturedCube class. It overrides mesh with an instance of CubeMesh to generate geometry. 

BlinnPhongLightedTexCube

BlinnPhongLightedTexCube is derived from TexturedCube class. It illuminates the textured cube as per settings done in the light parameter.

Members

Name	Description
cameraPosition	Specifies the location of the light source for diffuse and specular illumination.
light	An instance of PhongLightingUtil. It contains settings for illumination.

Methods

Name	Description
Init	This method overrides the base class Init method to load texture.  Generates the vertices data consisting of surface normals in non indexed mode and later sets them up in VBO buffer.
UpdateUniforms	This method overrides the base class UpdateUniforms method. Firs t it updates  "cameraposition" uniform. Next it updates lighting related uniforms by calling Updateshader method on light. Finally it c alls base class UpdateUniforms method to send rest.
vertexShaderSource	This method overrides the base class vertexShaderSource method. It returns the vertex shader code to render the cube object.
fragmentShaderSource	This method overrides the base class fragmentShaderSource method. It returns the fragment shader code to render the cube object.

BlinnPhongLightingUtil

It defines illumination properties of the light source and reflection properties of the material in the light and material members.

Members

Name	Description
material	An instance of Material sub class. It contains settings of the material property for reflection.
light	An instance of Light sub class. It contains settings for illumination.

Methods

Name	Description
UpdateShader	Updates the uniforms that contains copies of the information stored in light and material members.

Output